Candidate. I pursue this Mentored Patient-Oriented Research Career Development Award (K23) to facilitate my transition towards an independent research career in HIV prevention science. My long-term goal is to become a productive independent HIV prevention behavioral scientist. My goals include the development of HIV prevention interventions - using new and increasingly accessible and influential online media - to address disparities among sexual minority populations across key developmental periods. To date, my training has focused on core strengths and skills in clinical psychology (PhD) and epidemiology (MPH). I have acquired expertise in HIV prevention, behavior change theory, and research methods, with an emphasis on adults. This foundation has prepared me for the proposed next steps of my training, namely, developing expertise in adolescent risk behavior (the time when most risk behavior patterns are established) and the skills necessary for the development, implementation, and evaluation of online prevention interventions and research. Training plan. The proposed training plan will prepare me to work with adolescent sexual minority populations, a group at significant risk for HIV. Receipt of a K23 award will allow me protected time to acquire the necessary skills. Specifically, with the K23 training I will: (1) acquire the theoretical and methodological skills required for HIV prevention interventions targeting sexual minority populations during adolescence; (2) gain hands-on training in online media-based intervention development, including health communications and media literacy skills; and (3) build the necessary collaboration networks and research infrastructure to enable independence as an NIH-funded investigator. Importantly my training will also increase my sophistication regarding the (4) unique ethical challenges involved in (a) working with a young, often stigmatized population, and (b) delivering online interventions. Both domains are fraught with ethical complexities (e.g., privacy, consent, confidentiality) at a time of rapidly-evolving societal, cultural, health, and technological changes. My training will prepare me to take a leadership role in this emerging and complex research area. Training goals will be achieved through didactic courses, workshops, research experience, and mentoring. Environment. During the proposed K23, I will be a Research Scientist at The Miriam Hospital and an Assistant Professor at Brown University. At the Miriam, I will have access to the outstanding and highly supportive research environments provided by the Centers for Behavioral and Preventive Medicine and the Centers for AIDS Research. At Brown University, I will have access to the academic resources of the Schools of Medicine and Public Health, including the Alcohol Research Center on HIV. This environment will enhance my training and facilitate my research goals. Through the training, experience, and skills gained as a part of this K23 Award, I will be prepared to pursue funding to conduct a larger randomized controlled trial of an intervention to reduce HIV risk among adolescent sexual minority populations. Mentors. I will receive mentoring from an outstanding team of internationally recognized and accomplished investigators in HIV prevention and behavioral science, public health, communications, and media literacy. Proposed research. Young sexual minority males account for a disproportionate number of HIV infections in the United States. Racial and ethnic minority populations are particularly affected. Incidence rates reflect sexual risk behaviors during early sexual experiences. Research suggests that initial sexual risk-taking occurs during adolescence (ages 14-18) among sexual minority males. Therefore, it is important for HIV prevention interventions to target adolescent sexual minority males. Targeting sexual minority males during adolescence will help them learn and establish healthy sexual behaviors early in their psychosexual development, which will have both immediate and long-term health benefits. Online media use triggers and maintains sexual risk-taking among adolescent sexual minority males. Consequently, it is critical for HIV prevention interventions to address the influence of online media on this population. One way to address this influence is by developing an online sexual health media literacy intervention. To promote adolescent sexual minority males' critical examination of online media and to decrease their sexual risk-taking, I propose a two-stage program of research (i.e., formative research and an exploratory clinical trial) with three aims: (1) develop methods to recruit and retain a racially/ethnically diverse sample of adolescent sexual minority males online using feedback from five focus groups (N ~ 30); (2) develop a brief, online-administered, sexual health media literacy intervention to lower HIV risk behaviors among adolescent sexual minority males using information from a youth advisory board (N ~ 8) and a cross-sectional online survey (N = 200); and (3) conduct an exploratory clinical trial to pilot test the developed online sexual health media literacy intervention for feasibility and acceptability (N = 100). Overall, the proposed research has the potential to reach a wide audience of sexual minority males early in their sexual development, ultimately decreasing their sexual risk-taking and reducing the number of new HIV infections in this population. Further, the proposed research will expand my capacities as an HIV researcher and interventionist and place me at the forefront of online media-based HIV prevention research.